A strapping machine of the type noted above is exemplifed in Leslie et al. U.S. Pat. No. 4,154,158. As disclosed therein, a steel strap is fed from a strap dispenser, through a strap chute, and about an article being strapped so as to form a loop with a leading end segment of the strap overlapping an adjacent strap segment. The strap loop is gripped at its leading end while its trailing portions are retracted so as to draw the strap loop from the strap chute, around the article, and so as to tension the strap loop around the article. A sealless connection is made in the overlapped segments, by means of a punch and die assembly, and the layer connecting the strap loop to the remaining strap in the strap dispenser is cut so as to separate the strap loop. These feeding, gripping, tensioning, sealing, and cutting functions are performed by various components of a strapping head.
The Leslie et al. patent noted above refers to Beach U.S. Pat. No. 3,303,541 for further details of the sealless connection. Sealless connections of related interest are disclosed in Leslie U.S. Pat. No. 2,276,988, Partridge U.S. Pat. Nos. 3,188,706, Simmons 3,935,616, Cepuritis U.S. Pat Nos. 4,031,594, Duenser 4,048,697, Wojcik 4,062,086, Duenser 4,226,007, and Lems et al. U.S. Pat. No. 4,228,565.
As disclosed in the patents noted in the preceding paragraph, Z-shaped or other slits punched in two overlapped segments of a tensioned loop strapping form interlockable shoulders, which interlock when the loop is released under retained tension. Except for the Beach patent noted above, these patents also disclose various so-called "anti-reverse" locking features, which prevent relative movement of the overlapped, connected segments in such directions as would unlock the shoulder.
Thus, as an example, Leslie U.S. Pat. No. 2,276,988 discloses parallel transverse cuts made along respective edges of two overlapped, connected segments of strapping after a sealless connection has been made. The cuts form registering fingers, which are downwardly bent about longitudinal axes to prevent relative movement of the overlapped, connected segments in either longitudinal direction.
In the Tremper and Pearson application noted above, improvements in a sealless connection between two overlapped segments of strapping are disclosed. As disclosed therein, notches are cut from overlapped edges of the respective segments into the respective segments after shoulders therein have become interlocked with each other upon shifting of the respective segments longitudinally in relation to each other in a locking direction. The respective segments are formed at the notches, along axes oblique in relation to the respective segments, to prevent shifting of the respective segments in an opposite direction. Similar notches, at which the respective segments are formed similarly, are provided on opposite edges of the respective segments.